You will need the build-essential and linux-headers-generic packages to install. If you do not have these packages, you can find them on packages.ubuntu.com, download the *.deb files and manually install them.

linux-headers-generic is a virtual packages that installs the correct headers for the current kernel you're running. You can find that out by typing uname -r in the terminal. Mine is 3.0.0-17-generic. That means what I should really download is the linux-headers-3.0.0-17-generic package. Once you have your ethernet work, apt-get install linux-kernel-headers so you always have the correct headers.

The build-essential package has a lot of dependancies, and when you attempt to install the .deb file it will tell you what is missing. Go back to packages.ubuntu.com and download all of the *.debs for the packages it complains about.

If you're running Ubuntu, *.deb files can be installed by double clicking on them. On Kubuntu, you need to right click and choose the install option.

Build the module
Goto Davicom's website and download the LINUX Driver to your home folder.
Open up the Terminal and type tar -xzvf dm9601-Linux2.6_1_1 to extract it.
Type cd dm9601 to enter the newly created folder.
Type gedit dm9601.c to edit the broken source file.
Change #include <linux/config.h> to #include <linux/configfs.h>
Save the file and close gedit.
Type make to build the module.

Ok, now you've built the module. At this point we can test it. With your Davicom USB adapter plugged in, type sudo insmod dm9601.ko to temporarily insert the module. If everything works, we need to make this module insert automatically on bootup.

Insert the module on bootup
Type sudo cp dm9601.ko /lib/modules/$(uname -r)/kernel/ubuntu/net/
type sudo gedit /etc/modules
Add dm9601 on it's own line at the end of the file
Save and exit gedit.

Your module should now work on reboot. Congratulations! You will need to repeat steps 2,3 & 7 from the Build stage and step 1 from the Insert stage whenever you install a kernel update.

Troubleshooting
If insmod failed to work, you probably need to add your USB device ID to the header file.

Type 'lsmod' and look for a line that belongs to your Davicom USB adapter. It should look similar to "Bus 001 Device 006: ID 0a46:9555 Davicom Semiconductor, Inc." If you have doubt, unplug all other USB devices and find the only line that doesn't have "0000:0000".